Sales tax levy on the sale of goods or services, generally calculated as a percentage of the selling price, and sometimes called a purchase tax. It is usually collected in the form of an extra charge by the retailer, who remits the tax to the government. It may be levied each time a commodity changes hands—as from manufacturer to wholesaler, from wholesaler to retailer—and is then called a transactions, or turnover, tax. Many oppose the tax as being regressive, i.e., as placing a disproportionately heavy burden on the poor; but it yields a large revenue, and governments find it easy to collect. As of 1999, 45 states, the District of Columbia, a number of cities and counties, and many foreign countries levied sales taxes. A modern variant of the sales tax is the value-added tax.